Electrical contacts such as those projecting from a connector housing and those that are free standing, are commonly provided with compliant sections that can be press fit into plated circuit board holes and which resist pullout from the holes. One type of compliant section is the eye-of-the-needle type that has an elongated slot that divides the contact section into a pair of largely parallel spaced beams. The middles of the beams are deflected closer together when press fit into the circuit board hole.
For circuit board holes of at least twenty-five thousandths inch (with a typical allowable range of 25 to 31 thousandth inch), the simple eye-of-the-needle construction provides a holding or retention force (resistance to pull-out) of at least about 4.5 pounds, which is a minimum specified in many applications. However, for much smaller hole sizes such as twenty-two thousandths inch (a range such as 22 to 27 thousandths inch) or less, applicant finds that the simple eye-of-the-needle construction provides a holding force that is no more than about 1.5 pounds, which is considerably less than the minimum designated force of about 3.3 pounds (for a 22 thousandths inch minimum). The lower retention force is largely due to the fact that thinner sheet metal must be used. The need for a considerable retention force for small contacts that fit in very small holes, has been increasing as contacts have become smaller to accommodate the need for higher densities of contacts.